The phosphorylation of yeast inorganic pyrophosphatase and formation of stoichiometric amounts of enzyme-bound pyrophosphate
| Autor: | N.P. Bakuleva, Tatiana I. Nazarova, Alexander A. Baykov, Svetlana M. Avaeva |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Stereochemistry
Biophysics Saccharomyces cerevisiae Biochemistry Pyrophosphate Phosphates chemistry.chemical_compound Structural Biology Genetics Pyrophosphatases Molecular Biology chemistry.chemical_classification Inorganic pyrophosphatase Pyrophosphatase Binding Sites biology Active site Substrate (chemistry) Cell Biology Phosphate Yeast Diphosphates Inorganic Pyrophosphatase Kinetics Enzyme chemistry biology.protein |
| Zdroj: | FEBS Letters. (2):245-247 |
| ISSN: | 0014-5793 |
| DOI: | 10.1016/0014-5793(81)80147-0 |
| Popis: | 1. Introduction Baker’s yeast inorganic pyrophosphatase (EC 3.6.1 .I) is able to bind orthophosphate with a dissoci- ation constant of the order of 1 mM [l-3]. Despite the moderate strength of the binding, it results in formation of a chemical bond of an acyl phosphate type [4]. Since phosphate is the product of PPt hydrolysis and the substrate in the reverse reaction, one could have supposed the phosphorylated enzyme to be an obligatory catalytic intermediate. However, blocking the active site of the enzyme with pyrophos- phate did not eliminate Pi binding [5]. This observa- tion necessitated further studies of the reaction of pyrophosphatase with Pi. They were partly stimulated by the finding of N. N. Vorobjeva in this laboratory that the phosphorylated enzyme can be isolated by gel filtration in the absence of Mg*+. Here, the following features of the enzyme-phos- phate reaction are revealed: (i) A stoichiometric amount of protein-bound PP, forms from Pi in the active site of pyrophos- phatase; (ii) 0.5 mol Pi/m01 of active sites is independently bound in a different centre; (iii) The bound Pi and PPi are rapidly exchanged for medium phosphate in the presence of Mg*+. 2. Materials and methods Inorganic pyrophosphatase with spec. act. 600 IV/ mg at pH 7.2,25”C was isolated from baker’s yeast as |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|